Acoustical device



Dec. 12, 1939. FRANZBLAU 2,182,865

ACOUSTICAL DEVICE Filed March 4, 1958 INVENTOR L, Josquk MEwzzb/au BY M"\ M ATTORNEY Ilia/6b 17a, [71) a earphone.

Patented Dec. 12, 1939 UNITED STATES PATENT OFFICE 2,182,885 ACOUSTICAL DEVIQE Joseph M. Fransblau, Brooklyn, N. Y., assignor to Colonial Earphone Co. Inc., New York,

Application March 4, 1938, Serial No. 193,912

10Ciaims.

Devices of this general class are in extensive 8 use, most of them containing certain common elements such as a diaphragm, one or more carbon buttons engaging the diaphragm and electrically connected to a switch; and batteries. And in many devices of this character, the said 10 carbon buttons have a number of recessed portions each containing a plurality of very small carbon balls adapted for oscillatory engagement with the adjacent diaphragm. It is an accepted fact, however, that acoustical devices containing the above-rei'erred-to elements have cer-.

tain shortcomings, one of the most serious being the loss oi eillciency of the device due to fatigue of certain of these elements during continuous operation. For example, if the device 7 so has been used continuously over a period of time,

as it must of necessity be when employed as an earphone for a deaf person, the fatigue of the battery will begin to manifest itself by a 10s of eiliciency oi the receiver. The said diaphragmfiai engaging carbon buttons will also become subject to fatigue, as well as the above-reierred-to 7 carbon balls. The latter, because of theirshapeand size, and the mechanical and electrical action to which they are subjected, will have internal heat generated therein,--a iactor in iatigue,-with' -a consequent loss 01 eiliciency. Hencein most otthe acoustical devices containing the above elements, it i'requently becomes necessary to switch oil the current from the bata tery to give the various parts some rest, whereby they will be brought back to normal effectiveness ai'ter a period of time. Obviously, such an interruption oi operation is exceedingl'yinconvenient and annoying to the person using the lt is one of the objectives 01' my invention to obviate the above-mentioned shortcomings by enabling an acoustical device of this general structure to eiiectively remain in continuous use with practically no interruption because of tatigue of any oi the elements. And in this aspect 01 my invention, another obiect is to prolong the life of certainoi the,elements by enabling them, 4 to be periodically relieved of their respective opso erative loads without discontinuing the operation oithedevice. It is also within the-contemplation'oi my invention to provide a combination switch and rheostat that will conveniently enable the wearer g; 01' the acoustical device to alternately Put into operation certain supplementary elements when. it is noticed'that the effects of iatigueare be ginning to manifest themselves, whereby the device can be kept in continuous and uninterrupted "eii'ective use at all times. I ti Another object of my invention is to produce a longer effective life oi an acoustical diaphragm, particularly when made of carbon, by providing protective means against the bombardment of the above-referred-to carbon balls situated withlid in the recesses of the carbon buttons.

And still another object is to provide a device of this character with absorbing means for the purpose oi. eliminatingunwanted noises caused by the vibration of certain of the structural parts 15 of this device. And in this aspect of my invention, another object is to provide improved resonance means in a device of this character.

It is also within the contemplation .of my invention, in one form thereof, to enable two cargo bon diaphragm-en agi g buttons to be employed for alternate use whereby both of said buttons are sufllciently near the center of the diaphragm forefllcient operation.

- It is my further purpose to enable all the as above-stated obiectivesio be eflectuated and 'accomplished in a simple, readily constructed and compact structure.

Other objects, features and advantages will appearirom the drawing and the description so hereinafter given.

Referring to the drawing, i Figure 1 is a perspective rear view of the acoustical device constituting my invention, the back cover being removed. :5

Figure 2 is an enlarged rear view of the combination switch and rheostat shown inFlgure 1.

Figure 3 is a fragmentary vertical section taken substantially along line. 3-4 of Figure 1, the diaphragm casing and the switch and rheostat being shown in elevation.

Figure 4 is a section through the diaphragm casing taken along lines 4-4 of Figures 3 and 5.

Figure 5 is a sectionoi Figure 4 taken along line 5-4. 45

Figure 6 is a rear view of a modified form 01' the carbon buttons employed in this invention,

and

Figure 7 is a semi-diagrammatic representation of the elements of this invention, including 0 a wir dias m.

In the drawing, the outer casing or housing ll, over whichthe cover II is adapted to be positioned (as shown in Figure 3) contains therein the diaphragm casing l2 preferably supported by the clips l3 and I4 mounted on housing ID, the combination switch and rheostat I5 and two sets of batteries, one set consisting of the cells |3a and I31) and the other set consisting of the cells Na and I'll), these batteries being shown supported by the frame l3 suitably secured to the housing Id.

The said switch and rheostat l5 contains a disc-like member l9 of insulating material at the center 20' ofwhich is rotatably mounted the contact member 2| containing the radial arms 22 and 23 forming a continuous electrical conductor. The contact terminals or segments 24 and 25, made of a conducting material such as copper, are preferably slightly elevated above the level of disc l9 to enable ready contact to be made with the arm 22. separated by the recessed portion 26 which is radially continuous with the recess 21 for receiving a portion of the arm 22 when it is manipulated into its neutral position. The lower portion of the disc contains two independent coils of resistance wire 23 and 29, preferably slightly elevated above the disc l9 to enable ready contact to be made with the terminal 30 of arm 23. It will be noted that said coils 23 and 29 are separated by a recessed portion 3| which is adapted to receive the terminal 30 when the member 2| is rotated into neutral position. In the form illustrated, the disc I9 is shown with a circular groove 32 within which the contact bars 24 and 25 and the resistance wires 23 and 23 are set, this being a preferred arrangement. The terminal binding posts 33 and 34 are electrically connected to the bars 24 and 25 respec-' tively, and the binding'post s 35 and are connected to the resistance elements 23 and 29 respectively, it being understood that other forms of connecting means may beemployed-in lieu of said binding posts, within the scope of this of substantially cup-shaped recessed portions 43' and 43 each of these containing therein a plurality of small carbon balls 5|! and 5| respectively. Said buttons 45 and 4| are positioned in such close proximity to the diaphragm 33as to enable said carbon balls 53 and 5| to come into engagement with the rear surface of the diaphragm without dropping out through the space between the buttons and the diaphragm. Co'gnizance is takenof the fact that this button and ball arrangement is known in the art. The said buttons 43 and 4| are adjacent to each other but nevertheless separated by a gap 52, the adjacent portions of said buttons preferably being flat so as to bring both of the buttons closer to the center of the diaphragm than would be the case it they were both absolutely" circular. The inner or rear surface of the.;diaphragm 33 is'preferably gold-plated over at least the area thereof covered by the said buttons, the elliptical dot-dash line of Figure 4 showing the approximate limitations of said gold-plated area.

Said contact bars are will be obtained.

In the operation of this device, the balls 53 and 5| are caused to vibrate'to produce what in effect is a bombardment of the diaphragm 39. When a diaphragm is made of carbon, such a bombardment generally causes a gradual breaking away or wearing out of certain portions of the diaphragm, making frequent replacements necessary. By gold-plating the area thereof adjacent nular felt base 53-which in turn is mounted upon the metal screen 54 secured to the front plate 55.

of the housing II). This felt base 53 not only serves as an acoustic absorber to eliminate the interfering effects of the mechanical vibration of the metallic parts in the structure, but also serves as a spacer between the casing l2 and the screen 54, thereby providing a chamber 55 which will tend to enhance the resonance of the apparatus.

In describing the operation of this device, reference will particularly be made to Figures 1, 2

and 7 which show the electric conductors 5'! and 53 connecting the contact bars 24 and 25 with the corresponding buttons 43 and 4|, said conductors being attached to the terminals 33 and 34. The conductor 59 connects the resistance coil 23 to the set of batteries |6a and b, this conductor being secured to the terminal 35; and the conductor 33 connects the resistance coil-29 to the set of batteries Fla and "b, said-conductor being connected to the terminal 33. The receiver 5|, of conventional structure, is electrically connected by, the conductors 32 and 33 to the diaphragm 33 and the batteries, respectively.

v In settingthis device into operation, the protruding portion 22a of contact member 2| is manipulated to operatively rotate the member, whereby the arms 22 and 23 are brought into electrical contact with said contact bars andcorresponding resistance coilsl For example, by referring to Figures 2 and 7, the member 22 had been rotated slightly clockwise from the neutral spaces 23 and 2|,'so that the arm- 22 is shown to be in electrical engagement with the contact bar 25, and the arm 23 in electrical engagement with the resistance coil 23. This forms a complete circuit through the one set of batteries Ila and Nb, the diaphragm, the buttonsand the earphone receiver 5|, whereby the device is rendered operative. It is, of course, obvious that by continuing 'theclockwise rotation of member 22, more of the coils of'the;resistance element 23 will be cut out, and hence greater amplification 1: the device is maintahied in ntinuous use for a period of time in the above pomtion, fatigue will set in notonly within the batteries Ila and lib, but also within the button" and the carbon balls 53, for the reasons as aforesaid. The wearer of the device will generally be able to notice when this occurs by its decreased emciency. All

that he need hence do is tomove the. contact 'member 22 to the oppositely disposed resistance coil and contact segments. In "other words, by simply rotating member 22 from the position shown in Figure 2 to a positionwhere the arm 22 is brought into action, all without interrupting the operation of the entire device. The combination switch and rheostat of Figure 2 readily makes this operation possible, in view of the relative positioning of the rheostatic and contact elements, and the convenient location of the member 2| for manual manipulation.

In the form of carbon button shown in Figure 6, an interlocking arrangement is illustrated. The upper button 64 contains a recessed portion 65 within which the protruding portion 66 of the lower button 61 is positioned, the protruding portion 68 of button i4 extending within the recessed portion 69 of lower button 61. The arrangement is such as to bring both of the buttons closer towards the center of the diaphragm with which they are associated, thereby enabling each but-- ton to independently operate at greater efficiency than would be the case if these buttons were farther removed from said center. It will also be noted that the said buttons are of the general form of the buttons 4| and ll, and are also separated by a gap.

It is of course understood that the various embodiments above described and shown in the drawing are illustrative of employed by way of limitation, inasmuch as numerous changes and modifications may be made within the scope of the appended claims without departing from the spirit of this invention.

What I claim:

1. In an acoustical device, a housing, and suitably supported therein an electric battery, twoway switch means containing two independent contact terminals and a movable contact member selectively engageable upon manual manipulation alternately with either one or the other of said contact terminals, acoustical oscillating means containing a diaphragm and two adjacent but tons of conducting material adaptedfor operative engagement with the diaphragm and having portions flanking the center thereof, electric conducting-means connecting one of said'terminals with one of said buttons andv the other terminal to the other button, an earphone electrically connected to said diaphragm and said battery, and electrical conductors connected to the battery and adapted for engagement with said movable contact member whereby the earphone is operable by the circuit through either one or the other of the buttons, in accordance with the s'elective operative manipulation of the contact member. I 2. 'In an acoustical device, a housing, and suitably supported therein acoustical oscillating means, two independent electricbatteries, twoway switch means containing two independent contact terminals and a movable contact member selectively engageable upon manual manipulation alternately with either one or the other of said contact terminals, said oscillating means containing a diaphragm and two adjacent buttons of conducting material adapted for operatlve engagement with thediaphragm and adja- 1 said buttons and the other of my invention and not corresponding ,button, in accordance with the operative manipulation of the movable contact member. 3. In an acoustical device, a housing, and suitmeans, two independent ,electric batteries, twoway switch means containing two independent contact terminals, two corresponding independent resistance elements and a movable contact member operatively engageable upon selective manual manipulation with one or the other of said terminals and the corresponding resistance element, said acoustical means containing adia-v phragm and two adjacent buttons of conducting material adapted for operative engagement with the diaphragm and adjacent the central portion thereof, conducting means electrically connecting one of said terminals, its corresponding resistance element, one of said buttons and one of said batteries, and supplementary conducting means electrically connecting the other of said terminals its corresponding resistance element, the other of said batteries, and an earphone electrically connected to said diaphragm and said batteries, whereby the earphone is operable by the circuit through either one or the other of the batteries and through the corresponding button, in accordance with the operative manipulation of the movable contact membere 4. An-acoustical device containing the combination according to claim 3, the said buttons containing a plurality of recesses in facing relation to the diaphragm, and a plurality of relatively small balls of conducting material contained therein and engageable with said buttons and diaphragm'being spaced apart a distance less than the diameter of any of the balls.

5. An acoustical device containing the combination according to claim 3, the rear surface of the diaphragm being gold-platedover that portion thereof adjacent said buttons and adapted foroperative engagement therewith.

6. Inan acoustical device, a housing, and suitably supported therein acoustical oscillating means, two independent electric batteries twoway switch means containing two independent ably supported therein acoustical oscillating the diaphragm, tne

Of substantially the coil, said acoustical means containing a diacenter thereof, conducting, means electrically connecting one of said contact bars, its corresponding resistance coil, one of said buttons and one of said batteries, and supplementary conducting means electrically connecting the other of said contact bars, its corresponding resistance coil, the other of said buttons and the other of said batteries, and earphone electrically connected to said diaphragm and said batteries, whereby the earphone is operable by the circuit through either one or the other of the batteries and through the corresponding button, in accordance with the operative manipulation of the movable contact member.

7. In an acoustical device, a housing, and suitably supported therein acoustical oscillating means, two independent electric batteries, twoway switch means comprising a disc-like member vof insulating material, a contact member r0-, tatably mounted, at the center of the said discand containing two oppositely extending radial arms forming a continuous electrical conductor,

two independent adjacent contact'bars or substantially arcuate form disposed near a peripheral portion of the said disc and separated by a ,relatively small gap, two independent adjacent resistance coils of substantially arcuate iorm dis.-

- posed near a peripheral portion of said disc diametrically opposite to that of said contact bars and separated by a relatively small gap, the said opposite radial arms being adapted, upon an operative rotatable manipulation of the contact member, for simultaneous slidable engagement with either of said contact bars and the corresponding resistance coilwhen in an operative position, and for simultaneous positioning in both of saidgaps when in a* neutral position; said acousticai means containing a diap fll and bars, its corresponding resistance coil, the other of said buttons and the other of said batteries, and an earphone electrically connected to said diaphragm and said batteries, whereby the earphone is operable by the circuit through either one or the other of the batteries and through the corresponding button, in accordance with the operative manipulation of the movable contact member.

8. An apparatus according to claim 7 wherein the two-way switch means is contained within a casing having an aperture therein, a portion of one of said radial arms extending through said aperture whereby it can be grasped for manual manipulation.

=9. An apparatus according to claim- 7 wherein the said disc contains on a face thereof a circular groove, the said contact bars and resistance coils being partially set and retained within said groove, and partially extending therefrom above the surface of the disc, whereby the radial arms will form operative contact therewith without engaging the surface of the disc.

10, In an acoustical device the combination according to claim 6, further provided with a casing within whichvsaid acoustical oscillating means are operatively supported, said casing being contained within the said housing of the device and in spaced relation to the front wall thereof, and

an annular resilient base secured to the said front wall of the housing and upon which said casing is mounted, thereby providing a resonance chamber between the casing and the wall of the housing.

'JOSEPi-I M. FRANZBIAU, 

